Report Created: August 2024
A PurpleAir air quality monitoring sensor was installed at multiple sites within the CT DEEP monitoring network to evaluate the sensors performance tracking PM2.5 data against a reference. PurpleAir data was corrected using the extended U.S-wide correction equation developed by the EPA to reduce bias in sensor data (more information found here: AirNow). Hourly data from 2023 was then compared to a T640 reference monitor located at the same location. The full dataset used can be downloaded here Download CSV.
Site Locations
Sensor Details
PurpleAir Specifications
| Possible Configuration | Evaluated Configuration | Cost | Data Access | Power Supply | Considerations | Reference Monitor Compared |
| PM2.5, Temperature, Relative Humidity, Pressure | PM2.5 |
Sensor: $229 Outdoor Power Supply: $40 |
Micro SD card, WiFi connectivity, API download and live public online map | Potted 5V USB outdoor power supply 12 ft mains plug |
-Effected by saltwater (issues with coastal use) -Life Expectancy ~2 years |
PM2.5: Teledyne API T640X Temp & RH: AutoMet 580 |
Setup
Timeseries Comparison
PurpleAir hourly data for PM2.5 were compared by quarter to reference values from a T640 analyzer (Q1: January-March, Q2: April-June, Q3: July-September, Q4: October-December).
Bridgeport
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Cornwall
Quarter 1
Quarter 2
Quarter 3
Quater 4
Danbury
Quarter 1
Quarter 2
Quarter 3
Quarter 4
East Hartford
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Groton
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Hartford
Quarter 1
Quarter 2
Quarter 3
Quarter 4
New Haven
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Waterbury
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Correlation Comparison
PurpleAir and Reference Correlation
Bridgeport
Cornwall
Danbury
East Hartford
Groton
Hartford
New Haven
Waterbury
Results Summary
